Musical instrument



April 1938. F. A. HOSCHKE 2,113,347

MUS ICAL INSTRUMENT Filed April 14, 1956 2 Sheets-Sheet 1 April 1938. F.IA. HOSCHKE 2,113,347

MUS I CAL INSTRUMENT Filed April 14, 1936 2 Sheets-Sheet 2 2 a 9 '3 I Q 1x m 3 )1 q 0 Q4 I- r EH T0 8' PLUS Patented Apr. 1938 UNITED STATES.

PATENT OFFICE MUSICAL INSTRUMENT Application April 14, 1938, Serial No. 74,376

50laims.

My invention relates to improvements in musical instruments of the electronic type, and it consists in the combination, constructions, and arrangements herein described and claimed.

An object of my invention is to provide an improvement over that set forth in my prior Patent No. 2,015,014, dated September 1'7, 1935. In said prior patent an electronic musical instrument was disclosed in which a reed in vibration formed a portion. of one plate of a microphone condenser, the other plate having means for adjustment with respect to the reed for varyingthe capacitance of the condenser.

The present invention relates to an improvement in which the reeds themselves do not form a portion of the plate of the microphone condenser but in which diaphragms are provided, these diaphragms forming portions of one plate of the microphone condenser and in which )0 means is provided for adjusting the other plate inductively with respect to the diaphragms.

An object of the invention is to provide a construction which is particularly adapted to the picking up" of all of the harmonics that are 5 caused by the shape or the bending (prevoicing) of a reed particularly of the higher harmonics.

A further object of the invention is to provide a simple device by means of which condenser microphone diaphragms are provided which respond to compressed and rarified air impulses in strict pneumatic fashion.

Other objects and advantages will appear in the following specification and the novel features of the invention will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings, in which:

Figure l is a transverse sectional view through a portion of the instrument along the line i-l of Figure 2,-the amplifying circuit being shown in diagram,

Figure 2 is a plan view of the device along the line 2--2 of Figure 1, the amplifying circuit being omitted,

Figure 3 is an enlarged sectional view along the line 33 of Figure 1,

Figure 4 is a vertical sectional view along the line 44 of Figure 1,

50 Figure 5 is a sectional view showing a modified form,

Figure 6 is an enlarged sectional view along the line 3-60! Figure 5,

Figure! is a sectional view of a portion of a 55 modified form of the device, and

Figure 8 is a sectional view of a portion of another modiiied form of the device.

In carrying out the invention I make use of structure which is to be found in the ordinary reed organ. Referring particularly to Figure 4 5 I have shown therein a wind chest I, a reservoir or wind pressure regulator 2 having openings 3 for a suitable suction wind supply. The top part ofthe wind chest is formed by a pallet board 5 (see Fig. 1). On the underside of the pallet 10 board are pallets or valves 6 which are provided with a felt covering 1. It will be understood that there is a pallet for each key. Each pallet is normally held in the position shown in Figure l by means of a spring 8 carried by the pallet 15 board and is guided by pins 3 which extend through slots Ill at each end thereof. In Fig. 1 I have shown a single key ll, of the keyboard of the instrument, which is arranged to bear on a dowel I2 that passes through an opening I3 in the pallet board 5 for depressing the pallet or valve. 7

Mounted on the pallet board 5 is a cell section ll having a series of partitions l5 for forming cells. As will be seen from Figure 4 the walls of the partitions are slotted to receive the frames l6 which bear the reeds H, the latter being secured in any suitable manner such as by rivets, as shown in Figure 1, each reed being disposed over a slot l8 in the frame. The pallet board 5 has slots is which register with the slots l3 and the bottoms of these slots i3 are normally closed by the pallets 6.

The top H of the cell section H is provided with openings 2|] above each cell. An insulating block 2| (see Fig. 1) is provided for each reed or cell, that form of the block shown in Fig. 1 having a recess 22 into which the end of a screw 23 extends, the screw being threaded into the block. A nut 24 is carried by the screw for lock- 40 ing the latter in its adjusted position. The block 2| is held to the top ll of the cell section it in any suitable manner such as by screws 25.

As stated there is an adjustable screw for each diaphragm. The insulating blocks are arranged side by side as shown in Fig. 2 and a conducting strip 26 of tin foil or duraluminum foil is disposed overthe openings 20 and is held in taut position by means of the insulating blocks 2|. This provides a thin diaphragm of foil over each opening 20 and underneath the enlarged end of each screw 23.

The nuts, such as those shown at 24, not only serve for locking the screws 23 in adjusted position, but they also serve to clamp a conducting tube of a preamplifier.

strip 21 (see Fig. 2) to the tops of the insulating blocks 2|.

The conducting strip 21 is connected by means 01 a conductor 28 with the grid 29 of a suitable forms the diaphragms 26- is connected by means of a conductor 30 with the battery B of the radio circuit shown in Fig. 1. It will be understood that this is simply a typical circuit and forms no part of the present invention except as suchcircuit is used in connection with the apparatus for producing a tonal effect by the adjustment of the apparatus as presently described.

Consider now Figure 1. Let us assume that the key II is depressed and that through the medium of the dowel l2 and the pallet 6, communication is established between the cell section above the reed and the suction wind chest. Air entering the front end of the cell cavity is allowed to pass the reed which vibrates within the cell according to the frequency (fundamental and harmonics) of the reed. The constants of such fluctuation are determined by the nature of the air puffs caused by the movement of the reed, different shaped and voiced reeds causing difierent constants. The small diaphragm 26 in the ceiling of the cell cavity is therefore responsive to these fluctuations. Now these small diaphragms, which are all connected together, form portions of one plate of the microphone condenser and the screws which are electrically connected together form the opposite plate of the microphone condenser. The impulses are conveyed to a pre-amplifier, then further amplified and converted into sound in the loud speakers.

The entire control of tone quality rests in the prevoicing of the reed. The reed itself is out of the electric or electronic circuit and acts merely as a pneumatic valve. This arrangement differs from the conventional radio studio microphone in that the small diaphragms in the insulating units do not respond to sound waves like the conventional radio studio microphones do but rather to variations of the air flow or pressure controlled by the reeds. It is not the reed that makes the tone; it is the air puffs.

As stated above the reed in most instances is gives a quality of tone which is characteristic of a flat vibrating reed. The ends of the reed may be bent as shown in my prior Patent 2,015,014 to alter the tone quality to produce such effects as flute tones, clarinet tones, etc. In adjusting the mechanism the nut 24 is loosened and the screw 23 is'turned by means of pliers or any other suitable instrument as to bringthe lower end of the screw bearing the head into inductive relation with the diaphragm 26* until the desired amplitude is attained.

Figures 1 and 2- show one means of mounting the metal foil plate 26. In these figures the plate is cemented to the top I4 of the cell section.

tion. The foil diaphragm is placed on top of the member it and the insulating block 32 is forced downwardly, the boss 32" entering the opening The foil plate 26 which first prevoiced. A reed which is not prevoiced and stretching the diaphragm tightly as shown at 3|. The block is then screwed to the top l4" and the adjustment of the screw 23 is made as before stated. In this instance, the diaphragm 3|- is below the top l4 as distinguished from that form shown in Figure 1.

In Figure 7 I have shown a modified form in which one diaphragm covers two cavity cells instead of one, thereby reducing the diaphragms and tone screws to one-half their number. Thus in the figure the cell section l4 and the cell cavities I4 are in direct communication by means of a bore' 35 with the diaphragm 36 which spans the recess 31 in the insulating cover 38. The head of the tone screw 39 is disposed in the recess and the screw is held in position by the lock nut 40.

In this form of the device it will be observed that the tone screw is spaced symmetrically with respect to the reeds M and 42 so that the diaphragm covering the recess 31 is directly affected by the puifs of air generated by the vibration of both or either of the reeds 4| and 42.

In Figure 8, which is another modification, a block of wood 43 may besecured at any point in the wind chest on a mounted base 44. Theblock 43 has a recess 45 which is open to the atmos phere within the wind chest. A diaphragm 46 is stretched over this recess and over a recess 41 in an insulating block 48 having a tone screw 49.

Every time a pallet is opened by pressing a key a reed goes into vibration. In swinging back and forth the reed opens and closes the atmospheric current tending to pass the reed, thus creating impulses, these impulses having an eiIect upon the entire wind supply within the chest, expanding and contracting its contents or distributing the movement thereof to a degree sufficient to agitate a single diaphragm such as that shown at 46.

Such a simple diaphragm would not have the amplitude of one with each cell or two cells but this is compensated for by using additional tone screws over it, thereby increasing the pick-up. The close proximity between the tone screw and the diaphragm increases the tension of the electrostatic charge so that additional tone screws will increase the charge, as desired.

" By setting or fastening such a unit at or to the bottom, sides or top of the wind chest (inside of the latter) the diaphragm will pneumatically respond to air fluctuations caused by the swinging reed or reeds. A conductor 50 ,connects the tone screw 49 with the grid 28 (see Figure 1) while a similarconductor 51 connects the diaphragm to the B battery.

In the use of the-*dev-iceshown in Figure 8 individual diaphragms may be dispensed with although it will be understood that my preferred form is that in which individual diaphragms are used.

I claim:

1-. Ina musical instrument,. a plurality of reeds, each reed being disposed in an individual cell cavity, pneumaticmeans for selectively vibrating said reeds, a diaphragm associated with each cell cavity and adapted to beposcillate'd by pulsations of air from its vibrating reed, an adjustable conductor associated with each diaphragm on the opposite side thereof from the reed, said diaphragms belngin electrical connection'to form one plate of the microphone condenser, and said conducting members being in electrical connection with one. another to form the opposite plate of the condenser.

2. In a musical instrument, a plurality of prevoiced reeds, each reed being disposed in an individual cell cavity, pneumatic means for selectively vibrating said reeds, a diaphragm associated with each cell cavity and adapted to be oscillated by pulsations of air from its vibrating reed, an adjustable conductor associated with each diaphragm on the opposite sldethereoi from the reed, said diaphragms being in electrical connection to form one plate of the microphone condenser, said conducting members being in electrical connection with one another to form the opposite plate of the condenser, and an amplifying circuit working in conjunction with said microphone circuit.

8. In a musical instrument, a cell section having individual reed cavities, a reed associated with each cavity, each of said cell sections having an opening opposite the reed, a thin metal I 'movement 'of the diaphragms away from the reeds.

4. In a musical instrument, a cell section having individual reed cavities, a reed associated with each cavity, each 0! said cell sections having an opening opposite the reed, a thin metal strip covering said openings, that portion of the strip spanning the openings constituting 9. diaphragm for its associated cavity, an insulating block having recesses on the opposite side of the diaphragm corresponding to the openings of the cell cavities, thereby affording space for the movement of the diaphragms away from the reeds, and means for securing the block to the cell section whereby the metal strip is clamped in position.

5. In a musical instrument, a cell section having individual reed cavities, a reed associated with each cavity, each of said cell sections having an opening opposite the reed, a thin metal strip covering said openings, that portion of the strip spanning the openings constituting a diaphragm for its associated cavity, an insulating block having recesses on the opposite side of the diaphragm corresponding to the openings of the cell cavities, thereby affording space for the movement of the diaphragms away from the reeds, means for securing the block to the cell section whereby the metal strip is clamped in position, and an adjustable conductor disposed in each recess, said adjustable conductors being in electrical connection and forming one plate of a microphone condenser, and said metal strip forming the other plate.

FREDERICK A. HOSCHKE. 

